A conventional electric lamp base system shown in FIG. 3 includes a lamp base 10 having a cylindrical wall 101 defining a central hole for a lamp 20 to fit therein and two opposite wire feet 102, 102 formed in a lower portion of the cylindrical wall 101 for two lead wires 201, 201 of the lamp 20 to extend through down to the bottoms of the feet 102, 102 and to bend up to contact with two conductive copper pieces 303 connected with power wires 304, 304. The system also has a cylindrical socket 30 having an upper central hole 301 for the lamp base 10 to fit therein and a lower rectangular hole 302 for the wire feet 102,102 to fit therein. Two opposite conductive copper plates 303, 303 are provided on an inner surface of the rectangular hole 302 for contacting with the two lead wires 201, 201 of the lamp 20.
In manufacturing process, the lamp base 10 often has the central hole for the lamp 20 with its size not according to the planned one caused by shooting process with cool shrinking course, consequently the lamp 20 may move or loosen therein. In addition, the socket 30 is also made by plastic shooting process, with possible different size from the preset one so that the lamp base 10 may also move or loosen in the central hole 301 of the socket 30.